RESUMO
Recent advances have contributed to a mechanistic understanding of neuroimmune interactions in the intestine and revealed an essential role of this cross talk for gut homeostasis and modulation of inflammatory and infectious intestinal diseases. In this review, we describe the innervation of the intestine by intrinsic and extrinsic neurons and then focus on the bidirectional communication between neurons and immune cells. First, we highlight the contribution of neuronal subtypes to the development of colitis and discuss the different immune and epithelial cell types that are regulated by neurons via the release of neuropeptides and neurotransmitters. Next, we review the role of intestinal inflammation in the development of visceral hypersensitivity and summarize how inflammatory mediators induce peripheral and central sensitization of gut-innervating sensory neurons. Finally, we outline the importance of immune cells and gut microbiota for the survival and function of different neuronal populations at homeostasis and during bacterial and helminth infection.
Assuntos
Neuroimunomodulação , Humanos , Animais , Intestinos/imunologia , Homeostase , Microbioma Gastrointestinal/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Neurônios/metabolismo , Neurônios/imunologia , Neuropeptídeos/metabolismo , Sistema Nervoso Entérico/imunologia , Sistema Nervoso Entérico/metabolismoRESUMO
Behavior relies on activity in structured neural circuits that are distributed across the brain, but most experiments probe neurons in a single area at a time. Using multiple Neuropixels probes, we recorded from multi-regional loops connected to the anterior lateral motor cortex (ALM), a circuit node mediating memory-guided directional licking. Neurons encoding sensory stimuli, choices, and actions were distributed across the brain. However, choice coding was concentrated in the ALM and subcortical areas receiving input from the ALM in an ALM-dependent manner. Diverse orofacial movements were encoded in the hindbrain; midbrain; and, to a lesser extent, forebrain. Choice signals were first detected in the ALM and the midbrain, followed by the thalamus and other brain areas. At movement initiation, choice-selective activity collapsed across the brain, followed by new activity patterns driving specific actions. Our experiments provide the foundation for neural circuit models of decision-making and movement initiation.
Assuntos
Movimento , Neurônios , Encéfalo/fisiologia , Movimento/fisiologia , Neurônios/fisiologia , Tálamo/fisiologia , MemóriaRESUMO
Our understanding of how the brain assembles its circuits and how this goes awry in disease remains incomplete. There has been great progress in generating human neurons from stem cells in vitro and, more recently, in constructing circuits with human cells in vivo by transplantation. Here, I highlight approaches, promises, and challenges of growing human neurons in living animals to study human development and disease.
Assuntos
Encéfalo , Neurônios , Animais , Humanos , Células-TroncoRESUMO
A central question for regenerative neuroscience is whether synthetic neural circuits, such as those built from two species, can function in an intact brain. Here, we apply blastocyst complementation to selectively build and test interspecies neural circuits. Despite approximately 10-20 million years of evolution, and prominent species differences in brain size, rat pluripotent stem cells injected into mouse blastocysts develop and persist throughout the mouse brain. Unexpectedly, the mouse niche reprograms the birth dates of rat neurons in the cortex and hippocampus, supporting rat-mouse synaptic activity. When mouse olfactory neurons are genetically silenced or killed, rat neurons restore information flow to odor processing circuits. Moreover, they rescue the primal behavior of food seeking, although less well than mouse neurons. By revealing that a mouse can sense the world using neurons from another species, we establish neural blastocyst complementation as a powerful tool to identify conserved mechanisms of brain development, plasticity, and repair.
Assuntos
Neurônios , Animais , Camundongos , Ratos , Neurônios/metabolismo , Neurônios/citologia , Neurônios/fisiologia , Blastocisto/metabolismo , Blastocisto/citologia , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Encéfalo/citologia , Encéfalo/fisiologia , Feminino , Hipocampo/citologia , Hipocampo/fisiologia , Especificidade da Espécie , Camundongos Endogâmicos C57BL , MasculinoRESUMO
Proprioception tells the brain the state of the body based on distributed sensory neurons. Yet, the principles that govern proprioceptive processing are poorly understood. Here, we employ a task-driven modeling approach to investigate the neural code of proprioceptive neurons in cuneate nucleus (CN) and somatosensory cortex area 2 (S1). We simulated muscle spindle signals through musculoskeletal modeling and generated a large-scale movement repertoire to train neural networks based on 16 hypotheses, each representing different computational goals. We found that the emerging, task-optimized internal representations generalize from synthetic data to predict neural dynamics in CN and S1 of primates. Computational tasks that aim to predict the limb position and velocity were the best at predicting the neural activity in both areas. Since task optimization develops representations that better predict neural activity during active than passive movements, we postulate that neural activity in the CN and S1 is top-down modulated during goal-directed movements.
Assuntos
Neurônios , Propriocepção , Animais , Propriocepção/fisiologia , Neurônios/fisiologia , Encéfalo/fisiologia , Movimento/fisiologia , Primatas , Redes Neurais de ComputaçãoRESUMO
To understand biological processes, it is necessary to reveal the molecular heterogeneity of cells by gaining access to the location and interaction of all biomolecules. Significant advances were achieved by super-resolution microscopy, but such methods are still far from reaching the multiplexing capacity of proteomics. Here, we introduce secondary label-based unlimited multiplexed DNA-PAINT (SUM-PAINT), a high-throughput imaging method that is capable of achieving virtually unlimited multiplexing at better than 15 nm resolution. Using SUM-PAINT, we generated 30-plex single-molecule resolved datasets in neurons and adapted omics-inspired analysis for data exploration. This allowed us to reveal the complexity of synaptic heterogeneity, leading to the discovery of a distinct synapse type. We not only provide a resource for researchers, but also an integrated acquisition and analysis workflow for comprehensive spatial proteomics at single-protein resolution.
Assuntos
Proteômica , Imagem Individual de Molécula , DNA , Microscopia de Fluorescência/métodos , Neurônios , ProteínasRESUMO
Neuroimmune interactions mediate intercellular communication and underlie critical brain functions. Microglia, CNS-resident macrophages, modulate the brain through direct physical interactions and the secretion of molecules. One such secreted factor, the complement protein C1q, contributes to complement-mediated synapse elimination in both developmental and disease models, yet brain C1q protein levels increase significantly throughout aging. Here, we report that C1q interacts with neuronal ribonucleoprotein (RNP) complexes in an age-dependent manner. Purified C1q protein undergoes RNA-dependent liquid-liquid phase separation (LLPS) in vitro, and the interaction of C1q with neuronal RNP complexes in vivo is dependent on RNA and endocytosis. Mice lacking C1q have age-specific alterations in neuronal protein synthesis in vivo and impaired fear memory extinction. Together, our findings reveal a biophysical property of C1q that underlies RNA- and age-dependent neuronal interactions and demonstrate a role of C1q in critical intracellular neuronal processes.
Assuntos
Envelhecimento , Encéfalo , Complemento C1q , Homeostase , Microglia , Neurônios , Ribonucleoproteínas , Animais , Complemento C1q/metabolismo , Camundongos , Microglia/metabolismo , Envelhecimento/metabolismo , Encéfalo/metabolismo , Ribonucleoproteínas/metabolismo , Neurônios/metabolismo , Camundongos Endogâmicos C57BL , HumanosRESUMO
Characterizing somatic mutations in the brain is important for disentangling the complex mechanisms of aging, yet little is known about mutational patterns in different brain cell types. Here, we performed whole-genome sequencing (WGS) of 86 single oligodendrocytes, 20 mixed glia, and 56 single neurons from neurotypical individuals spanning 0.4-104 years of age and identified >92,000 somatic single-nucleotide variants (sSNVs) and small insertions/deletions (indels). Although both cell types accumulate somatic mutations linearly with age, oligodendrocytes accumulated sSNVs 81% faster than neurons and indels 28% slower than neurons. Correlation of mutations with single-nucleus RNA profiles and chromatin accessibility from the same brains revealed that oligodendrocyte mutations are enriched in inactive genomic regions and are distributed across the genome similarly to mutations in brain cancers. In contrast, neuronal mutations are enriched in open, transcriptionally active chromatin. These stark differences suggest an assortment of active mutagenic processes in oligodendrocytes and neurons.
Assuntos
Envelhecimento , Encéfalo , Neurônios , Oligodendroglia , Humanos , Envelhecimento/genética , Envelhecimento/patologia , Cromatina/genética , Cromatina/metabolismo , Mutação , Neurônios/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Análise da Expressão Gênica de Célula Única , Sequenciamento Completo do Genoma , Encéfalo/metabolismo , Encéfalo/patologia , Polimorfismo de Nucleotídeo Único , Mutação INDEL , Bancos de Espécimes Biológicos , Células Precursoras de Oligodendrócitos/metabolismo , Células Precursoras de Oligodendrócitos/patologiaRESUMO
Inflammation-induced neurodegeneration is a defining feature of multiple sclerosis (MS), yet the underlying mechanisms remain unclear. By dissecting the neuronal inflammatory stress response, we discovered that neurons in MS and its mouse model induce the stimulator of interferon genes (STING). However, activation of neuronal STING requires its detachment from the stromal interaction molecule 1 (STIM1), a process triggered by glutamate excitotoxicity. This detachment initiates non-canonical STING signaling, which leads to autophagic degradation of glutathione peroxidase 4 (GPX4), essential for neuronal redox homeostasis and thereby inducing ferroptosis. Both genetic and pharmacological interventions that target STING in neurons protect against inflammation-induced neurodegeneration. Our findings position STING as a central regulator of the detrimental neuronal inflammatory stress response, integrating inflammation with glutamate signaling to cause neuronal cell death, and present it as a tractable target for treating neurodegeneration in MS.
Assuntos
Inflamação , Proteínas de Membrana , Esclerose Múltipla , Neurônios , Animais , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Camundongos , Humanos , Inflamação/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Transdução de Sinais , Autofagia , Camundongos Endogâmicos C57BL , Ácido Glutâmico/metabolismo , Ferroptose , Modelos Animais de Doenças , Feminino , MasculinoRESUMO
The vasculature of the central nervous system is a 3D lattice composed of laminar vascular beds interconnected by penetrating vessels. The mechanisms controlling 3D lattice network formation remain largely unknown. Combining viral labeling, genetic marking, and single-cell profiling in the mouse retina, we discovered a perivascular neuronal subset, annotated as Fam19a4/Nts-positive retinal ganglion cells (Fam19a4/Nts-RGCs), directly contacting the vasculature with perisomatic endfeet. Developmental ablation of Fam19a4/Nts-RGCs led to disoriented growth of penetrating vessels near the ganglion cell layer (GCL), leading to a disorganized 3D vascular lattice. We identified enriched PIEZO2 expression in Fam19a4/Nts-RGCs. Piezo2 loss from all retinal neurons or Fam19a4/Nts-RGCs abolished the direct neurovascular contacts and phenocopied the Fam19a4/Nts-RGC ablation deficits. The defective vascular structure led to reduced capillary perfusion and sensitized the retina to ischemic insults. Furthermore, we uncovered a Piezo2-dependent perivascular granule cell subset for cerebellar vascular patterning, indicating neuronal Piezo2-dependent 3D vascular patterning in the brain.
Assuntos
Cerebelo , Neurônios , Retina , Animais , Feminino , Masculino , Camundongos , Cerebelo/metabolismo , Cerebelo/irrigação sanguínea , Cerebelo/citologia , Canais Iônicos/metabolismo , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Retina/citologia , Retina/metabolismo , Células Ganglionares da Retina/metabolismo , Vasos Retinianos/metabolismoRESUMO
Hypothalamic neural circuits regulate instinctive behaviors such as food seeking, the fight/flight response, socialization, and maternal care. Here, we identified microdeletions on chromosome Xq23 disrupting the brain-expressed transient receptor potential (TRP) channel 5 (TRPC5). This family of channels detects sensory stimuli and converts them into electrical signals interpretable by the brain. Male TRPC5 deletion carriers exhibited food seeking, obesity, anxiety, and autism, which were recapitulated in knockin male mice harboring a human loss-of-function TRPC5 mutation. Women carrying TRPC5 deletions had severe postpartum depression. As mothers, female knockin mice exhibited anhedonia and depression-like behavior with impaired care of offspring. Deletion of Trpc5 from oxytocin neurons in the hypothalamic paraventricular nucleus caused obesity in both sexes and postpartum depressive behavior in females, while Trpc5 overexpression in oxytocin neurons in knock-in mice reversed these phenotypes. We demonstrate that TRPC5 plays a pivotal role in mediating innate human behaviors fundamental to survival, including food seeking and maternal care.
Assuntos
Depressão Pós-Parto , Neurônios , Obesidade , Canais de Cátion TRPC , Animais , Feminino , Camundongos , Obesidade/metabolismo , Obesidade/genética , Masculino , Humanos , Canais de Cátion TRPC/metabolismo , Canais de Cátion TRPC/genética , Depressão Pós-Parto/metabolismo , Neurônios/metabolismo , Núcleo Hipotalâmico Paraventricular/metabolismo , Camundongos Endogâmicos C57BL , Ocitocina/metabolismo , Comportamento MaternoRESUMO
The hippocampus is critical for episodic memory. Although hippocampal activity represents place and other behaviorally relevant variables, it is unclear how it encodes numerous memories of specific events in life. To study episodic coding, we leveraged the specialized behavior of chickadees-food-caching birds that form memories at well-defined moments in time whenever they cache food for subsequent retrieval. Our recordings during caching revealed very sparse, transient barcode-like patterns of firing across hippocampal neurons. Each "barcode" uniquely represented a caching event and transiently reactivated during the retrieval of that specific cache. Barcodes co-occurred with the conventional activity of place cells but were uncorrelated even for nearby cache locations that had similar place codes. We propose that animals recall episodic memories by reactivating hippocampal barcodes. Similarly to computer hash codes, these patterns assign unique identifiers to different events and could be a mechanism for rapid formation and storage of many non-interfering memories.
Assuntos
Aves , Hipocampo , Memória Episódica , Animais , Aves/fisiologia , Comportamento Alimentar , Alimentos , Hipocampo/citologia , Hipocampo/fisiologia , Neurônios/citologiaRESUMO
Microglia are brain-resident macrophages that shape neural circuit development and are implicated in neurodevelopmental diseases. Multiple microglial transcriptional states have been defined, but their functional significance is unclear. Here, we identify a type I interferon (IFN-I)-responsive microglial state in the developing somatosensory cortex (postnatal day 5) that is actively engulfing whole neurons. This population expands during cortical remodeling induced by partial whisker deprivation. Global or microglial-specific loss of the IFN-I receptor resulted in microglia with phagolysosomal dysfunction and an accumulation of neurons with nuclear DNA damage. IFN-I gain of function increased neuronal engulfment by microglia in both mouse and zebrafish and restricted the accumulation of DNA-damaged neurons. Finally, IFN-I deficiency resulted in excess cortical excitatory neurons and tactile hypersensitivity. These data define a role for neuron-engulfing microglia during a critical window of brain development and reveal homeostatic functions of a canonical antiviral signaling pathway in the brain.
Assuntos
Encéfalo , Interferon Tipo I , Microglia , Animais , Camundongos , Interferon Tipo I/metabolismo , Microglia/metabolismo , Neurônios/metabolismo , Peixe-Zebra , Encéfalo/citologia , Encéfalo/crescimento & desenvolvimentoRESUMO
Somatic and sympathetic tones fluctuate together seamlessly across daily behaviors. In this issue of Cell, Zhang et al. describe populations of spinal projecting neurons in the rostral ventromedial medulla (rVMM) that harmonize somatic motor function and sympathetic activation. The coordinated regulation plays a vital role in supporting behaviors associated with various arousal states.
Assuntos
Tronco Encefálico , Bulbo , Publicações Periódicas como Assunto , Animais , Nível de Alerta/fisiologia , Sistema Nervoso Autônomo/fisiologia , Tronco Encefálico/fisiologia , Bulbo/fisiologia , Neurônios/fisiologia , Sistema Nervoso Simpático/fisiologia , Nervos Espinhais/fisiologiaRESUMO
Leveraging AAVs' versatile tropism and labeling capacity, we expanded the scale of in vivo CRISPR screening with single-cell transcriptomic phenotyping across embryonic to adult brains and peripheral nervous systems. Through extensive tests of 86 vectors across AAV serotypes combined with a transposon system, we substantially amplified labeling efficacy and accelerated in vivo gene delivery from weeks to days. Our proof-of-principle in utero screen identified the pleiotropic effects of Foxg1, highlighting its tight regulation of distinct networks essential for cell fate specification of Layer 6 corticothalamic neurons. Notably, our platform can label >6% of cerebral cells, surpassing the current state-of-the-art efficacy at <0.1% by lentivirus, to achieve analysis of over 30,000 cells in one experiment and enable massively parallel in vivo Perturb-seq. Compatible with various phenotypic measurements (single-cell or spatial multi-omics), it presents a flexible approach to interrogate gene function across cell types in vivo, translating gene variants to their causal function.
Assuntos
Redes Reguladoras de Genes , Análise de Célula Única , Animais , Feminino , Humanos , Camundongos , Córtex Cerebral/metabolismo , Córtex Cerebral/citologia , Sistemas CRISPR-Cas/genética , Dependovirus/genética , Fatores de Transcrição Forkhead/metabolismo , Fatores de Transcrição Forkhead/genética , Vetores Genéticos/metabolismo , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/metabolismo , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Neurônios/citologia , Análise de Célula Única/métodos , Transcriptoma/genética , Linhagem Celular , Transcrição GênicaRESUMO
High-resolution electron microscopy of nervous systems has enabled the reconstruction of synaptic connectomes. However, we do not know the synaptic sign for each connection (i.e., whether a connection is excitatory or inhibitory), which is implied by the released transmitter. We demonstrate that artificial neural networks can predict transmitter types for presynapses from electron micrographs: a network trained to predict six transmitters (acetylcholine, glutamate, GABA, serotonin, dopamine, octopamine) achieves an accuracy of 87% for individual synapses, 94% for neurons, and 91% for known cell types across a D. melanogaster whole brain. We visualize the ultrastructural features used for prediction, discovering subtle but significant differences between transmitter phenotypes. We also analyze transmitter distributions across the brain and find that neurons that develop together largely express only one fast-acting transmitter (acetylcholine, glutamate, or GABA). We hope that our publicly available predictions act as an accelerant for neuroscientific hypothesis generation for the fly.
Assuntos
Drosophila melanogaster , Microscopia Eletrônica , Neurotransmissores , Sinapses , Animais , Encéfalo/ultraestrutura , Encéfalo/metabolismo , Conectoma , Drosophila melanogaster/ultraestrutura , Drosophila melanogaster/metabolismo , Ácido gama-Aminobutírico/metabolismo , Microscopia Eletrônica/métodos , Redes Neurais de Computação , Neurônios/metabolismo , Neurônios/ultraestrutura , Neurotransmissores/metabolismo , Sinapses/ultraestrutura , Sinapses/metabolismoRESUMO
Many behaviors require the coordinated actions of somatic and autonomic functions. However, the underlying mechanisms remain elusive. By opto-stimulating different populations of descending spinal projecting neurons (SPNs) in anesthetized mice, we show that stimulation of excitatory SPNs in the rostral ventromedial medulla (rVMM) resulted in a simultaneous increase in somatomotor and sympathetic activities. Conversely, opto-stimulation of rVMM inhibitory SPNs decreased both activities. Anatomically, these SPNs innervate both sympathetic preganglionic neurons and motor-related regions in the spinal cord. Fiber-photometry recording indicated that the activities of rVMM SPNs correlate with different levels of muscle and sympathetic tone during distinct arousal states. Inhibiting rVMM excitatory SPNs reduced basal muscle and sympathetic tone, impairing locomotion initiation and high-speed performance. In contrast, silencing the inhibitory population abolished muscle atonia and sympathetic hypoactivity during rapid eye movement (REM) sleep. Together, these results identify rVMM SPNs as descending spinal projecting pathways controlling the tone of both the somatomotor and sympathetic systems.
Assuntos
Bulbo , Medula Espinal , Sistema Nervoso Simpático , Animais , Masculino , Camundongos , Locomoção/fisiologia , Bulbo/fisiologia , Camundongos Endogâmicos C57BL , Neurônios Motores/fisiologia , Neurônios/fisiologia , Sono REM/fisiologia , Medula Espinal/fisiologia , Sistema Nervoso Simpático/fisiologia , Comportamento Animal , Contagem de Células , Músculo EsqueléticoRESUMO
Tauopathies are age-associated neurodegenerative diseases whose mechanistic underpinnings remain elusive, partially due to a lack of appropriate human models. Here, we engineered human induced pluripotent stem cell (hiPSC)-derived neuronal lines to express 4R Tau and 4R Tau carrying the P301S MAPT mutation when differentiated into neurons. 4R-P301S neurons display progressive Tau inclusions upon seeding with Tau fibrils and recapitulate features of tauopathy phenotypes including shared transcriptomic signatures, autophagic body accumulation, and reduced neuronal activity. A CRISPRi screen of genes associated with Tau pathobiology identified over 500 genetic modifiers of seeding-induced Tau propagation, including retromer VPS29 and genes in the UFMylation cascade. In progressive supranuclear palsy (PSP) and Alzheimer's Disease (AD) brains, the UFMylation cascade is altered in neurofibrillary-tangle-bearing neurons. Inhibiting the UFMylation cascade in vitro and in vivo suppressed seeding-induced Tau propagation. This model provides a robust platform to identify novel therapeutic strategies for 4R tauopathy.
Assuntos
Células-Tronco Pluripotentes Induzidas , Neurônios , Tauopatias , Proteínas tau , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteínas tau/metabolismo , Tauopatias/metabolismo , Tauopatias/patologia , Neurônios/metabolismo , Neurônios/patologia , Animais , Camundongos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/genética , Encéfalo/metabolismo , Encéfalo/patologia , Paralisia Supranuclear Progressiva/metabolismo , Paralisia Supranuclear Progressiva/patologia , Paralisia Supranuclear Progressiva/genética , Diferenciação Celular , Mutação , AutofagiaRESUMO
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) share many clinical, pathological, and genetic features, but a detailed understanding of their associated transcriptional alterations across vulnerable cortical cell types is lacking. Here, we report a high-resolution, comparative single-cell molecular atlas of the human primary motor and dorsolateral prefrontal cortices and their transcriptional alterations in sporadic and familial ALS and FTLD. By integrating transcriptional and genetic information, we identify known and previously unidentified vulnerable populations in cortical layer 5 and show that ALS- and FTLD-implicated motor and spindle neurons possess a virtually indistinguishable molecular identity. We implicate potential disease mechanisms affecting these cell types as well as non-neuronal drivers of pathogenesis. Finally, we show that neuron loss in cortical layer 5 tracks more closely with transcriptional identity rather than cellular morphology and extends beyond previously reported vulnerable cell types.
Assuntos
Esclerose Lateral Amiotrófica , Degeneração Lobar Frontotemporal , Córtex Pré-Frontal , Animais , Humanos , Camundongos , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Demência Frontotemporal/genética , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/metabolismo , Degeneração Lobar Frontotemporal/patologia , Perfilação da Expressão Gênica , Neurônios/metabolismo , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/patologia , Análise da Expressão Gênica de Célula ÚnicaRESUMO
Metabolic changes are essential for neurodevelopmental processes. However, little is known about how and when neuronal metabolic remodeling occurs to promote functional circuits. In this issue of Cell, Knaus et al. demonstrate that a temporary perinatal shift in metabolites and lipids is crucial for cortical neurons' survival and wiring.